Sympathoexcitatory effect of hypothalamic/hypophysary inhibitory factor in rats

Hypertension
B S HuangFrans H H Leenen

Abstract

We recorded changes in arterial blood pressure, heart rate, and renal sympathetic nerve activity in response to intracerebroventricular injection of bovine hypothalamic/hypophysary inhibitory factor and ouabain in conscious Wistar rats. Ouabain at 0.3 to 0.6 microgram caused dose-related increases in blood pressure, heart rate, and nerve activity (peak increases: 19 +/- 2 mm Hg, 42 +/- 4 beats per minute, and 48 +/- 4%, respectively; P < .05 versus basal). These responses were all blocked by central antibody Fab fragments, which bind ouabain and related steroids with high affinity. The inhibitory factor significantly increased blood pressure but decreased heart rate and nerve activity. Dose-dependent increases in blood pressure as well as heart rate and nerve activity were observed when the inhibitory factor was injected after intravenous injection of the vasopressin antagonist D-(CH2)5Tyr-(Me)AVP. Central Fab fragments, however, did not affect these responses. Both ouabain and the inhibitory factor inhibited Na+,K+-ATPase activity in vitro. Fab fragments blocked this inhibition by ouabain but not by the inhibitory factor. These data indicate that the ouabainlike sympathoexcitatory effect of this factor is masked probably by a ...Continue Reading

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Citations

Apr 25, 2000·Journal of Cardiovascular Pharmacology·G CargnelliS Bova
Apr 9, 1998·Clinical and Experimental Hypertension : CHE·A S BudzikowskiF H Leenen
Jun 16, 2011·Neurochemistry International·Masamichi YoshikaHakuo Takahashi
May 8, 2004·American Journal of Physiology. Heart and Circulatory Physiology·Bing S HuangFrans H H Leenen
Oct 3, 2001·Physiological Reviews·H E de Wardener
Jul 31, 1998·Clinical and Experimental Hypertension : CHE·J W Van Huysse, F H Leenen
Aug 23, 2002·Experimental Biology and Medicine·Renata I Dmitrieva, Peter A Doris

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